The Gunnar Berg occurrence is located on a branch of the Tootsee River south of and near the Yukon-British Columbia border, approximately 85 kilometres west-southwest of the community of Watson Lake, Yukon.

Banded and brecciated skarn outcrops within a package of east to southeast dipping Lower Devonian Tapioca Sandstone dolomite, quartzite, and argillite just east of quartz monzonitic rocks the Early Cretaceous Cassiar batholith. Fine disseminated scheelite occurs throughout the skarn zones close to a quartzite-dolomite contact. Molybdenite occurs on fracture planes in one skarn and in quartz veins in the intrusion. A quartzite breccia zone, about 46 metres in length, contains blebs of galena and/or sphalerite. Two discontinuous chip samples taken across 12 metres assayed 429.3 grams per tonne silver (George Cross Newsletter No.235, December 6, 1984). Several trenches expose mineralization near the ridge crest.

In 1979, anomalous tungsten values were noted in stream sediment samples taken by Dupont, which later led to follow-up exploration and staking of the JCS 1-2 mineral claims. Dupont conducted geological mapping and geochemical soil sampling with detailed soil sampling and bulldozer sampling carried out on a tungsten skarn zone and also on a reported silver-lead showing (later Gunnar Berg) on the northern portion of the detailed grid. The JCS claims were subsequently allowed to lapse. In 1983, the Sue 1-2 claims were staked and eventually transferred to Turner Energy and a structural geology study was carried out. In 1984, preliminary bulldozer trenching of the silver-lead breccia zone occurred and a VLF-EM and geochemical soil sampling survey were carried out over 57 kilometres of grid. An eight-hole, 540 metre diamond drill program was completed in October of 1984 but the work was not filed for assessment. Based on the drilling it appears that the breccia zone is a sheet or tabular shaped body dipping approximately 30 degrees to the northeast with grades enriched on surface due to a probable cross structure. Further exploration and drilling were recommended to further delineate the higher grade zone. The tungsten-bearing skarn zone previously explored by Dupont in 1979 was not explored during the 1984 work. Work in 1984 in an area termed the south grid near the southern claims boundary of the Sue and now Big Ranch claim (ca. 2007) and immediately north of the Berg showing (104O 015, held by Silver Standard) outlined a zone in excess of 500 by 500 metres with values greater than 1000 parts per million (ppm) zinc, 250 ppm lead and 0.2 ppm silver. This substantial soil geochemical anomaly appears to have never been followed up. In 2007, Cazador Resources Ltd. collected 7 rock samples mostly along old trench cuts at the Gunnar Berg showing.